Common interfaces are VGA, DVI, HDMI and DP.
There are of course other type of interfaces,
This paper mainly introduces the above four interfaces,
This paper introduces the basic specifications, parameters and shapes of the interface,
And the connections and differences between these four interfaces.
VGA interface video graphics array,
I.e. a video graphics array,
Also known as D-Sub interface.
VGA interface transmits analog signals.
This interface has almost been eliminated at present,
Only a few projectors or instruments are still in use.
The VGA interface is a d-type interface,
* * * There are 15 stitches, which are divided into 3 rows with 5 stitches in each row.
The connection between computers and external display devices in the early days was through VGA interface.
Display the image information generated by digital inside the computer,
Converted into RGB primary color signals and line field synchronization signals by a D/A (digital/analog) converter in the graphics card,
The signal is transmitted to the display device through the cable.
For analog display devices, such as CRT displays,
The signal is directly sent to the corresponding processing circuit,
Driving and controlling a picture tube to generate an image;
For digital display devices such as LCD and DLP,
A corresponding A/D converter should be configured in the display device.
Convert analog signals into digital signals.
After two D/A and A/D conversions,
At the same time, the anti-interference ability of analog signals is very weak.
Inevitably, some image details will be lost.
It is understandable that VGA interface is applied to CRT display.
But for connecting a display device such as a liquid crystal,
Some signals will be lost, which will lead to the degradation of image quality.
Digital video interface,
Namely a digital video interface.
There are 3 types and 5 specifications of DVI interface.
DVI interface in the transmission of digital signals can be divided into
Single link and double link.
Three kinds: DVI-A, DVI-D and DVI-I.
Five specifications: DVI-A, DVI-D single connection, DVI-D double connection,
DVI-I single connection, DVI-I double connection.
Keywords digital video interface, simulation,
Pure analog interface only supports the transmission of analog signals.
Pin specifications (12+5).
The DVI-A interface still transmits analog signals.
So there is no essential difference with VGA interface.
DVI-D digital number,
Pure digital interface only supports the transmission of digital signals.
Pin specifications (18+ 1).
Pin specifications (24+ 1).
Comprehensive mixing,
The interface supports the transmission of analog and digital signals.
It is a transitional product.
Pin specifications (18+5).
Pin size (24+5).
DVI-I dual connection interface is widely used at present.
The transmission rate of a single DVI interface is only half that of a dual connection,
The maximum resolution and refresh rate can only be supported to 1920x 1200, 60hz.
Maximum resolution and refresh rate of dual DVI interface,
Can support 2560x 1600, 60Hz mode,
The modes of 1920x 1080 and 120 Hz can also be supported.
The LCD must have a refresh rate of 120Hz to achieve 3D effect.
Therefore, when DVI interface connection is used in the 3D scheme,
You must use a cable with dual DVI interfaces.
The obvious disadvantage of DVI interface is that it does not support the transmission of audio signals.
And the volume of the interface is very large.
HDMI interface, high definition multimedia interface,
Namely high-definition multimedia interface.
HDMI is an all-digital video and sound transmission interface.
But also can simultaneously transmit audio and video signals,
Because audio and video signals use the same wire,
The system circuit can be greatly simplified.
HDMI can not only meet the resolution of 1080P,
It can also support digital audio formats,
Support eight-channel 96kHz or stereo 192kHz digital audio transmission,
It can transmit uncompressed audio signals and video signals.
HDMI supports EDID, DDC2B,
So devices with HDMI have the characteristics of "plug and play".
There will be automatic "negotiation" between the signal source and the display device.
Automatically select the most suitable video/audio format.
Compared with DVI, HDMI interface is smaller.
The optimal cable length of HDMI/DVI is less than 8m.
There are currently four types of HDMI interfaces:
Type a, type b, type c and type d.
Type A is a full-size standard HDMI interface with 19 pins.
This is the most common and commonly used interface.
Type B interface supports higher resolution of 29 pins.
However, there is still no manufacturer using type B connector.
The size of c-type and d-type interfaces is reduced,
Also known as mini and micro interfaces,
These two interfaces are more used in portable products.
You need to pay royalties to use HDMI interface.
Copyright fees are divided into annual membership fees and product sales fees.
The cost has increased, and the price of products has also increased.
The HDMI interface is not particularly good at supporting high-quality output.
Although the new HDMI interface protocol can support 4K,
However, most of the HDMI interfaces of monitors sold in the market have not been upgraded.
So for users who need high resolution, other interfaces can be considered.
DP interface display port,
Is a standardized digital video interface standard.
DP is designed to replace traditional VGA and DVI interfaces.
It can be regarded as an upgraded version of HDMI interface.
This interface does not require authentication and authorization.
It is mainly used for the connection between video sources and devices,
It also supports carrying audio, USB and other forms of data.
In addition to connecting devices,
DP can also be used as an interface inside the device,
Even the data interface between chips.
DisplayPort can be used to transmit audio and video simultaneously.
Each of which can be transmitted separately without the other.
Thanks to the good performance, advanced technology and free features of DP interface,
At present, almost all high-end monitors come standard with DP interface.
At the same time, many graphics cards also come standard with one or more DP interfaces.
There are two types of DP interfaces:
1 is standard, similar to USB, HDMI and other connectors;
The second type is Mini, which is mainly aimed at applications with limited connection area.
Such as ultra-thin notebook computers.
This paper introduces four common display interfaces,
The selection of the input interface of the graphics card is summarized as follows:
If a monitor smaller than 20 inches is used,
Although image details will be lost,
The VGA interface is still applicable;
If a display with a resolution low than 1920* 1200 is used,
You can choose DVI-I, DVI-D, HDMI and DP interfaces.
The screen size of the monitor has little influence;
If an ultra-high resolution display is used,
Such as 2560* 1600 or building a multi-screen display output system,
You can choose DVI-D dual connection, HDMI and DP interface;
If a 3D display is used,
The resolution is below 1920* 1080,
You can choose DVI-D, HDMI and DP interfaces.
The resolution is above 2560* 1600,
It is best to choose HDMI and DP output interfaces.
It is best to choose a monitor whose video interface corresponds to the motherboard and graphics card.
For example, if the video card has an HDMI interface, use a monitor with an HDMI interface.
One-to-one correspondence between two interfaces is the best.
If it really doesn't work, consider interface conversion (not recommended).